Intake wheel motors

[Jared Russell]

Originally Posted by Ginger Power

Another tip for intake wheels when it comes to selecting the right gear ratio and motors: Your "intake velocity" aka the linear speed of your intake wheels should be greater than the max speed of your drivetrain. This makes it easier for you to intake a game piece while driving at it full speed.

As a huge fan of fast intakes on a team with a reputation for building fast intakes...

I've heard this rule of thumb parroted around a lot, but (in my experience) this can lead to teams building drastically undergeared intakes that stall at the first sign of trouble.

There is more that goes into a roller intake than speed, and high speed can bring with it some drawbacks. For most game objects that FIRST has given us, an effective intake requires carefully crafted geometry, materials selection, and deformation characteristics to work well. You may find that your mechanism is loaded in such a way during intaking that in order to prevent a stall when loaded AND run at a greater tip velocity than your maximum drive speed when unloaded would require a ludicrous amount of power. Or, you may find that a high tip velocity breaks static friction between the roller and game object when the robot isn't at full speed (i.e. most of the time).

It's really more of an impedance matching problem than a raw speed maximization problem (though adding more POWER to the equation usually helps). A lot of these tradeoffs are non-obvious and difficult to estimate from first principles, but can be the difference between a ridiculously effective and totally ineffective intake. Every team guesses wrong on total intake power and speed/torque from time to time. Unless you have the ability to quickly remake a custom transmission in-house, you really can't beat the VersaPlanetary for being able to quickly change your mind and adjust any or all of the power parameters of your mechanism.

[jwfoss]

When I think about fast robot intakes, nothing comes to mind more then FRC95's robot from 2002.

That being said, the RS775-18V will be greatly missed in the future for its size to power ratio. I'll all for throwing as much power as you can at an intake within the confines of weight and design. Looks like Mini-CIMs, BAGs, and 9015s for the future.

[Everett33]

Originally Posted by jwfoss

When I think about fast robot intakes, nothing comes to mind more then FRC95's robot from 2002.

That being said, the RS775-18V will be greatly missed in the future for its size to power ratio. I'll all for throwing as much power as you can at an intake within the confines of weight and design. Looks like Mini-CIMs, BAGs, and 9015s for the future.

Here is a video of their intake in action.
https://www.youtube.com/watch?v=jL6VtO5VSd8

[arc25565]

Thanks to everyone for all the suggestions. This has been very helpful.

[thinker&planner]

95 in 2002 looks amazing. But so does this.

[JesseK]

Originally Posted by thinker&planner

95 in 2002 looks amazing. But so does this.

Wow! Pretty amazing intake.

[Charger]

well, i learned it in a hard way but i can say that using andymark motors with gearboxes (like pg71) are a bit ineficient, in our aerial assist year we used pg71's in intake and it takes forever for it to get the ball totally. Last year we used window motors in our intake mechanism, it was better than pg71's but still it was too slow. However, this year, there was a special offseason event in Turkey with game of 2006, aim high and we built another robot for that offseason. In that robot we decided to use mini CIM motor connected to a CIMple box connected to wheels with chains and i can say that it almost worked perfectly. Still, bag motors with plenataries will probably be better but we dont have that much oppurtunutiy and parts in Turkey so we have never been able to test that.

[GeeTwo]

With PG71s, it's hard to get the wheel big enough for a decent tip speed. PG27s are nearly three times as fast. We used a PG-27 with a 6" wheel for our Aerial Assist pickup. For our tennis ball pickup in offseason, we used BAG motors and 5:1 reduction - plenty fast even with a 4" wheel; almost too fast for our purposes (we had a few balls jam inside until we made some adjustments).

[Charger]

Originally Posted by GeeTwo

With PG71s, it's hard to get the wheel big enough for a decent tip speed. PG27s are nearly three times as fast. We used a PG-27 with a 6" wheel for our Aerial Assist pickup. For our tennis ball pickup in offseason, we used BAG motors and 5:1 reduction - plenty fast even with a 4" wheel; almost too fast for our purposes (we had a few balls jam inside until we made some adjustments).

Wheels are good, but using tubes connected to motors are considerable too. With right measurements, you get a larger connection with ball and it makes it easier to take the ball.

[GeeTwo]

Originally Posted by Charger

Wheels are good, but using tubes connected to motors are considerable too. With right measurements, you get a larger connection with ball and it makes it easier to take the ball.

What size, shape, orientation, and material tubes are you talking about? How do you mount them to the motors?

[Charger]

Originally Posted by GeeTwo

What size, shape, orientation, and material tubes are you talking about? How do you mount them to the motors?

https://www.youtube.com/watch?v=JScN8XKEF-s

here is my old team's offseason robot. They used cylinders connected to mini cim and cimple box via chain. and I remember robots using cylinders in 2014 game such as cheesy poofs

[Ty Tremblay]

Originally Posted by GeeTwo

What size, shape, orientation, and material tubes are you talking about? How do you mount them to the motors?

Here's a new product from CRP.

[GeeTwo]

Originally Posted by Charger

https://www.youtube.com/watch?v=JScN8XKEF-s

here is my old team's offseason robot. They used cylinders connected to mini cim and cimple box via chain. and I remember robots using cylinders in 2014 game such as cheesy poofs

??????????? The only way I could make sense of your earlier post was if you were using "tubes" that were bigger and softer than a 6" wheel; what you were talking about was neither; smaller than most wheels and not apparently grippier. You certainly wouldn't want to run those off of a PG71, or even a PG27.

Continuing with the rollers yes, we did horizontal rollers with belts on our 2012 Rebound Rumble robot. In that case, we were using the belt run as our "storage area" for up to (IIRC) four balls. As such, we wanted the rollers to run slowly. The balls were soft enough that we could drive over them even without the rollers turning. Once they were trapped between the rollers and a backing sheet of plastic, we turned on the rollers to do the pickup. We powered those rollers with a window motor; It took about two or three seconds for a ball to make it from the floor all the way up to the trigger mechanism. But I didn't think of those as intakes so much as pickups; perhaps too subtle a distinction.

[EricH]

Originally Posted by jwfoss

When I think about fast robot intakes, nothing comes to mind more then FRC95's robot from 2002.

That being said, the RS775-18V will be greatly missed in the future for its size to power ratio. I'll all for throwing as much power as you can at an intake within the confines of weight and design. Looks like Mini-CIMs, BAGs, and 9015s for the future.

Looked at the date of this post... went "Oh, that was BEFORE VEX announced their new products". I'm now ducking and covering from the hail of RS775-18s flying my way as they're replaced by the VEX counterpart...

[Chris is me]

At this point, seems like the best choices are between the BAG, the mini-CIM, or the 775Pro.

The BAG is great if you want a lighter motor, don't need a ton of power, but your intake might stall. It's also better if you're trying to watch your current draw as it draws less current than the mini-CIM or 775.

The 775 has a lot more power at a similar weight, so if you can spare the current and don't think the intake will ever stall, it's a great choice.

If you need both power and stall protection, and don't mind the weight penalty, than a mini-CIM is the way to go.

In any case, in this modern era of FRC there is simply no better choice than a VersaPlanetary for gearing an intake. The weight penalty is worth it in exchange for the extreme flexibility in gearing options. Your intake should definitely run through a VP, unless you're very sure of the gear ratio and you need every ounce of weight you can get.